Blower valve



Feb.21,1939. I 7 .J.sANLA'N- 2,1 7,8 1

BLOWER VALVE Filed April 16, 1957 2 Sheets-Sheet 1 Feb. 21, 1939. c. JSCANLAN BLOWER VALVE Filed April 16, 1937 2 Sheets-Shee 3mm 'izesier JJean Zan Patented Feb. 21, 1939 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to an improved valve for a blower which isparticularly adapted for use in connection with a boiler or furnace ofthe under-feed type, but it is to be understood that .5 it may be usedin connection with the fire-box of any furnace.

Blowers as now constructed consist of a pipe or conduit having one endportion extending into the boiler or furnace under the grates of thefirebox and a fan housing at the outer end of the pipe from which air isforced through the pipe and up through a head at the inner end of thepipe for passage through the fire-box. Such blowers have not been foundentirely satisfactory,

this being particularly true when used with a furnace of the under-feedtype as when the fan is automatically shut off sufficient air to createa good combustion will be lacking and 'coal in the fire-box willcoke, v

Therefore, one object of this invention is to provide a valve for ablower having its conduit or pipe so constructed that, when the fan isshut off, the valve provided intermediate the length of the pipe will beopened and thus allow suflicient air to enter for supporting combustionin the fire-box and causing the coal to burn evenly instead of volatilegases being driven off and coke being formed.

Another object of the invention is to so construct the auxiliary airinlet intermediate the length of the pipe or conduit and so constructand mount the valve for this auxiliary air inlet that, when the bloweris not in use, the valve will turn to a vertical position and permit airto enter the conduit, the valve when in this vertical position extendingdownwardly into the conduit to such an extent that, when the fan isturned on, the blast of air passing through the pipe to the furnace willact upon the valve and move it to a closed position and thus prevent theair from escaping through the auxiliary air inlet instead of passinginto the furnace or boiler under the grate and upwardly through the coalin the fire-box.

Another object of the invention is to so construct the auxiliary airinlet that movement of the pivoted valve plate in a closing directionmay be limited and a tight closure formed when the valve plate is in theclosing position.

It is another object of the invention to provide means for limitingmovement of the valve in the opening direction and also to provide theauxiliary air inlet with a hood which will act as a shield and preventashes or other matter from dropping through the inlet into the conduitor pipe and interfering with proper movement of the valve or freepassage of air through the conduit when the blower is in operation.

The invention is illustrated in the accompanying drawings, whereinFigure 1 is a view partially in side elevation and partially in sectionshowing the improved blower in operative relation to a boiler,

Figure 2 is a sectional view taken longitudinally through the air pipeand the auxiliary air inlet of the blower,

Figure 3 is a top plan view of Figure 2,

Figure 4 is a view similar to Figure 2 illustrating a modifiedconstruction wherein a hood is provided for the auxiliary air inlet andan adjustable abutment provided to limit opening movement of the valve,and

Figure 5 is a sectional view taken along the line 55 of Figure 4.

The furnace or boiler I is of a conventional construction and is formed.with the usual fire-box having a grate 2 at its bottom, the grate beingdisposed at the top of a pit 4 from which air passes upwardly throughthe grate and through the pit of coal in the fire-box. A stoker, whichis indicated in general by the numeral 5, is provided for supplying coalto the fire-box. This stoker is of the under-feed type and coal is fedfrom the stoker into the fire-box in the usual manner.

In order to supply an adequate draft of air, there has been provided ablower consisting of an air pipe or conduit 6 which may be of any lengthand diameter desired. One end portion of this conduit or pipe extendsinto the pit 4 under the grate 2 and terminates in an upwardly extendingoutlet head 1 through which air passes upwardly and after leaving thedischarge head flows upwardly through the grate and through the bed ofcoal in the fire-box. At its outer end the conduit 6 is connected with afan housing 8 in which a rotary fan 9 is mounted. A side wall of the fanhousing has been shown formed with an air inlet l0, and it will beunderstood that both side walls may be similarly formed with air inletsso that, when the fan is in operatiomair may be drawn into the housingand then forced through the air pipe or conduit 6 to the head 1 at theinner end thereof and upwardly from this head through the fire-box. Thefan will be automatically turned on and off when necessary by controlmeans of a conventional construction. While the openings I0 in the sidewalls of the housing 8 permit a certain amount of air to enter the fanhousing when the fan is shut off and pass through the conduit or pipe 6,a sufiicient quantity of air to support combustion is lacking and as aresult volatile gases are driven off, thus leaving the fixed carbon inthe form of coke. This coke forms a somewhat solid mass through whichthe air does not properly penetrate when the fan is again turned on andthe coal in the fire-box does not burn properly.

In order to prevent the formation of coke, the conduit or pipe 6 hasbeen provided with an auxiliary air inlet intermediate its lengththrough which suflicient air may enter the conduit when the fan is shutoif and thus support combustion which will cause the coal in thefire-box to burn slowly without forming coke. The auxiliary air inlet isin the form of a neck I I which rises from the air pipe or conduit 6intermediate the length thereof and is open at its upper end, as shownin Figure 2. Flanges I2 and I3, which may be referred to as a lowerflange and an upper flange, extend about marginal portions of the openupper end of the neck I I, and it should be noted that the flangesextend across the opposite ends of the neck with their arms extendingalong side portions. of the neck. The arms of the flange I3 extendtoward the arms of the flange I2 but are in a higher plane than theflange I2 and its arms, and they terminate in spaced relation to ends ofthe arms of the flange I2. Therefore, when the valve I4 is in thevertically disposed or opened position, it may extend vertically betweenthe spaced ends of the arms, as shown in Figure 1 and as indicated bydotted lines in Figure 2. This valve is in the form of a plate which maybe sheet metal and intermediate its length is formed with a transverselyextending bearing I5 through which a pivot rod I6 passes with ends ofthe rod projecting from opposite sides of the plate and rotatablyengaged through side walls of the neck II. The plate or valve willthusbe pivotally mounted for swinging movement from the opened position,indicated by dotted lines in Figure 2, to the closed position shown infull lines in this figure, and attention is called to the fact that thevalve is so balanced that, when the fan is shut off, the valve willswing to the opened position and air may enter through the upper end ofthe neck and pass through the air pipe or conduit 6 and up through thehead I at the inner end thereof. Therefore, sufficient air will besupplied for supporting combustion and the coal in the flrebox will burnslowly instead of the volatile gases being driven off and coke beingformed. When the fan is turned on, the blast of air passing through theair pipe will strike the lower end of the valve plate and swing thisplate upwardly to the closed position where it will make contact withthe flanges I2 and I3 and close the upper end of the auxiliary air inletneck. This will cause all of the air from the fan to pass through theair pipe to the head I and upwardly from this head through the coal inthe fire-box. It will thus be seen that the auxiliary air inlet will beclosed when the fan is in operation and prevent air from escapingthrough this air inlet neck, whereas when the fan is shut off, the valvewill move to the open position and air will be permitted to enter theair pipe.

In Figures 4 and 5, there has been illustrated a modified construction.In this embodiment of the invention, the auxiliary air inlet or neck IIof the air pipe or conduit I8 is provided with internal flanges I9 and2!] instead of having upper marginal portions of its walls bent inwardlyto form the flanges. These flanges serve the same purpose as the flangesI2 and I3, and between spaced ends of their arms a valve plate 2I ispivotally mounted by a pivot pin 22 extending transversely of the valveplate through a bearing 23. A screw 24 serving as an abutment tolimit'movement of the valve in the opening direction is threaded throughan opening formed in one wall of the neck and a nut 25 is provided uponthis screw so that, when the screw has been; properly adjusted to permitopening of the valve plate to the desired position, the nut may betightened and the screw secured in the adjusted position. 'Side wallsofthe neck I'I extend upwardly above end walls thereof and are united toeach other to form a hood 26 which serves very effectively to preventashes and other foreign matter from accidentally dropping through theneck into the air pipe and creating an obstruction which would be liableto interfere with free movement of the valve into or out of an openedposition and also interfere with movement of air through the air pipe.End portions of the hood are extended beyond end walls of the neck II,as shown at 21, to effectively guard the neck and prevent material fromdropping into the neck. While the hood will very efiectively preventashes and other material from accidentally dropping into the neck, itwill not prevent the desired flow of air through the neck and into theair pipe when the fan is shut off.

Having thus described the invention, what is claimed as new is:

In a device of the character described, an air pipe, a neck extendingupwardly from the air pipe about an opening formed therein andconstituting an auxiliary air inlet, a valve plate pivotally mounted insaid neck for tilting movement about a horizontal axis from a verticalopened position to a horizontal closed position across the neck, upperand lower flanges mounted horizontally in the neck against walls thereofand disposed at opposite sides of the axis for engaging opposite facesof the valve plate and limiting closing movement of the valve, anopenended hood for the upper end of said neck constituting means forpreventing foreign matter entering the neck, and a screw carried by theneck and constituting an adjustable abutment for engagement by the valveplate to limit movement of the valve in an opening direction.

' CHESTER J. SCANLAN.

